Angel of Sealing

Flying, ward {3}
When Angel of Sealing enters the battlefield,
seal target nonland permanent. (Exile that card
with a seal counter on it. For as long as it has a seal counter on, it has ''Exile a card from your hand,
Remove a seal counter from this card: Put this card
into your hand. Activate only as a sorcery.'')
Sealed cards can't be unsealed.